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Pinto L, Soares G, Próspero A, Stoppa E, Biasotti G, Paixão F, Santos A, Oliveira R, Miranda J. An easy and low-cost biomagnetic methodology to study regional gastrointestinal transit in rats. ACTA ACUST UNITED AC 2021; 66:405-412. [PMID: 33544465 DOI: 10.1515/bmt-2020-0202] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 01/19/2021] [Indexed: 12/12/2022]
Abstract
The identification of gastrointestinal (GI) motility disorders requires the evaluation of regional GI transit, and the development of alternative methodologies in animals has a significant impact on translational approaches. Therefore, the purpose of this study was to validate an easy and low-cost methodology (alternate current biosusceptometry - ACB) for the assessment of regional GI transit in rats through images. Rats were fed a test meal containing magnetic tracer and phenol red, and GI segments (stomach, proximal, medial and distal small intestine, and cecum) were collected to assess tracer's retention at distinct times after ingestion (0, 60, 120, 240, and 360 min). Images were obtained by scanning the segments, and phenol red concentration was determined by the sample's absorbance. The temporal retention profile, geometric center, gastric emptying, and cecum arrival were evaluated. The correlation coefficient between methods was 0.802, and the temporal retention of each segment was successfully assessed. GI parameters yielded comparable results between methods, and ACB images presented advantages as the possibility to visualize intrasegmental tracer distribution and the automated scan of the segments. The imaging approach provided a reliable assessment of several parameters simultaneously and may serve as an accurate and sensitive approach for regional GI research in rats.
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Affiliation(s)
- Leonardo Pinto
- Department of Biophysics and Pharmacology, São Paulo State University, Biosciences Institute of Botucatu, Botucatu, Brazil
| | - Guilherme Soares
- Department of Biophysics and Pharmacology, São Paulo State University, Biosciences Institute of Botucatu, Botucatu, Brazil
| | - André Próspero
- Department of Biophysics and Pharmacology, São Paulo State University, Biosciences Institute of Botucatu, Botucatu, Brazil
| | - Erick Stoppa
- Department of Biophysics and Pharmacology, São Paulo State University, Biosciences Institute of Botucatu, Botucatu, Brazil
| | - Gabriel Biasotti
- Department of Biophysics and Pharmacology, São Paulo State University, Biosciences Institute of Botucatu, Botucatu, Brazil
| | - Fabiano Paixão
- Science and Technology Institute, Federal University of São Paulo, São José dos Campos, Brazil
| | - Armênio Santos
- Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, Brazil
| | - Ricardo Oliveira
- Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, Brazil
| | - José Miranda
- Department of Biophysics and Pharmacology, São Paulo State University, Biosciences Institute of Botucatu, Botucatu, Brazil
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Pinto LA, Corá LA, Rodrigues GS, Prospero AG, Soares GA, de Andreis U, de Arruda Miranda JR. Pharmacomagnetography to evaluate the performance of magnetic enteric-coated tablets in the human gastrointestinal tract. Eur J Pharm Biopharm 2021; 161:50-55. [PMID: 33592280 DOI: 10.1016/j.ejpb.2021.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 12/30/2022]
Abstract
A magnetic enteric-coated tablet containing diclofenac sodium was produced, and its performance under physiological and disturbed gastrointestinal motility was assessed through pharmacomagnetography analysis. In vitro studies were performed using conventional methods and in vivo studies were conducted on healthy volunteers before (control) and after domperidone administration. The magnetic tablet's gastrointestinal (GI) transit and disintegration process were monitored using the Alternating Current Biosusceptometry sensors combined with drug plasmatic concentration. The Gastric Residence Time, Colon Arrival Time, Small Bowel Transit Time, Disintegration Time and the pharmacokinetics parameters were calculated. The pH-dependent polymers used to coat the magnetic tablets were able to avoid the premature drug release on gastric or small intestine simulated medium. Gastric Residence Time was accelerated compared with the control group (p < 0.01). No significant differences were found regarding small bowel transit, colon arrival, disintegration process, or pharmacokinetics parameters. A strong correlation between magnetic monitoring and pharmacokinetics parameters analysis was determinant to evaluate the efficiency in the drug delivery at a specific site in the human gastrointestinal tract. In addition, a tablet with a damaged coating was used as a proof of concept to show the suitability of our methodology to evaluate the tablet. Our study showed that pharmacomagnetography is a multi-instrumental approach towards assessing drug delivery and bioavailability.
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Affiliation(s)
- Leonardo Antonio Pinto
- São Paulo State University - UNESP, Department of Biophysics and Pharmacology, Institute of Biosciences, Botucatu, São Paulo 18618-689, Brazil.
| | - Luciana Aparecida Corá
- Alagoas State University of Health Sciences- UNCISAL, Center of Integrative Sciences, Maceio, Alagoas 57010-382, Brazil.
| | - Gustavo Serafim Rodrigues
- São Paulo State University - UNESP, Department of Biophysics and Pharmacology, Institute of Biosciences, Botucatu, São Paulo 18618-689, Brazil.
| | - Andre Gonçalves Prospero
- São Paulo State University - UNESP, Department of Biophysics and Pharmacology, Institute of Biosciences, Botucatu, São Paulo 18618-689, Brazil.
| | - Guilherme Augusto Soares
- São Paulo State University - UNESP, Department of Biophysics and Pharmacology, Institute of Biosciences, Botucatu, São Paulo 18618-689, Brazil.
| | - Uilian de Andreis
- São Paulo State University - UNESP, Department of Biophysics and Pharmacology, Institute of Biosciences, Botucatu, São Paulo 18618-689, Brazil
| | - José Ricardo de Arruda Miranda
- São Paulo State University - UNESP, Department of Biophysics and Pharmacology, Institute of Biosciences, Botucatu, São Paulo 18618-689, Brazil.
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Nunes ADC, Gomes-Silva LA, Zufelato N, Prospero AG, Quini CC, Matos RVR, Miranda JRA, Bakuzis AF, Castro CH. Albumin Coating Prevents Cardiac Effect of the Magnetic Nanoparticles. IEEE Trans Nanobioscience 2019; 18:640-650. [PMID: 31398127 DOI: 10.1109/tnb.2019.2931962] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have showed that surface layer can determine cardiac effects of the magnetic nanoparticles (MNPs). Considering the high binding capacity of albumin and low side-effects, the aim of this study was to evaluate the influence of albumin coating on the cardiovascular effects of two manganese ferrite-based MNPs: citrate-coated and bare MNPs. Isolated rat hearts were perfused with citrate-coated magnetic nanoparticles (CiMNPs), citrate albumin-coated magnetic nanoparticles (CiAlbMNPs), bare magnetic nanoparticles (BaMNPs), and albumin-coated magnetic nanoparticles (AlbMNPs). CiMNPs induce a transient decrease in the left ventricular end-systolic pressure, +dP/dt and -dP/dt. These effects were not worsened by albumin coating. BaMNPs significantly increased the left ventricular end-diastolic pressure and perfusion pressure and decreased the +dP/dt and -dP/dt. These effects were completely absent in hearts perfused with AlbMNPs. None of the MNPs changed heart rate or arterial blood pressure in conscious rats. Magnetic signals in isolated hearts perfused with BaMNPs were significantly higher than AlbMNPs perfused hearts. However, the magnetic signal in heart tissue was similar when the MNPs were infused in conscious rats. These data indicate that albumin-coated can reduce cardiovascular effects of MNPs. These findings suggest a protective effect of albumin surface in MNPs, favoring its future therapeutic applications.
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Calabresi MFF, Quini CC, Matos JF, Moretto GM, Americo MF, Graça JRV, Santos AA, Oliveira RB, Pina DR, Miranda JRA. Alternate current biosusceptometry for the assessment of gastric motility after proximal gastrectomy in rats: a feasibility study. Neurogastroenterol Motil 2015; 27:1613-20. [PMID: 26303680 DOI: 10.1111/nmo.12660] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/25/2015] [Indexed: 12/12/2022]
Abstract
BACKGROUND This study proposes an experimental model to assess the consequences of gastric surgeries on gastric motility. We investigated the effects of proximal gastrectomy (PG) using a non-invasive technique (alternate current biosusceptometry [ACB]) on gastric contractility (GC), gastric emptying (GE), and orocecal transit (OCT) after the ingestion of liquids and solids in rats. METHODS Twenty-four male rats were subjected to gastric motility assessment before and after the PG procedure. The GE and OCT results are expressed as the mean time of gastric emptying (MGET) and cecum arrival (MCAT). The GC recordings are presented as the frequency and amplitude of contractions. KEY RESULTS Mean time of gastric emptying after solid meals were significantly different (p < 0.001) between control and PG (113 ± 5 to 99 ± 6 min). Mean time of cecum arrival ranged from 265 ± 9 to 223 ± 11 min (p < 0.001) and 164 ± 9 to 136 ± 17 min (p < 0.050) for solid and liquid meals, respectively. The assessment of GC showed that surgery decreased the phasic frequency (4.4 ± 0.4 to 3.0 ± 1.1 cpm, p < 0.050) and increased the amplitude of contractions (3.6 ± 2.7 to 7.2 ± 3.0 V/s, p < 0.050). No significant difference was found in tonic frequency. CONCLUSIONS & INFERENCES The ACB system was able to assess GE, OCT, and GC in gastrectomized rats. Overall, PG accelerated GE and gastrointestinal transit, likely due to the increase in both intragastric pressure and amplitude contraction. Our data presented an efficient model to investigate functional consequences from gastric surgeries that will allow further studies involving different procedures.
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Affiliation(s)
- M F F Calabresi
- Departamento de Física e Biofísica, Instituto de Biociências de Botucatu, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
| | - C C Quini
- Departamento de Física e Biofísica, Instituto de Biociências de Botucatu, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
| | - J F Matos
- Departamento de Física e Biofísica, Instituto de Biociências de Botucatu, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
| | - G M Moretto
- Departamento de Física e Biofísica, Instituto de Biociências de Botucatu, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
| | - M F Americo
- Instituto de Ciências Biológicas e da Saúde, UFMT-Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso, Brazil
| | - J R V Graça
- Departamento de Fisiologia, Faculdade de Medicina de Sobral, UFC-Universidade Federal do Ceará, Sobral, Ceará, Brazil
| | - A A Santos
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, UFC-Universidade Federal do Ceará, Fortaleza, Ceará, Brazil
| | - R B Oliveira
- Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, USP-Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - D R Pina
- Departamento de Doenças Tropicais e Diagnóstico por Imagem, Faculdade de Medicina de Botucatu, UNESP - Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
| | - J R A Miranda
- Departamento de Física e Biofísica, Instituto de Biociências de Botucatu, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
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Martins ML, Orecchini A, Aguilera L, Eckert J, Embs J, Matic A, Saeki MJ, Bordallo HN. Encapsulation of paclitaxel into a bio-nanocomposite. A study combining inelastic neutron scattering to thermal analysis and infrared spectroscopy. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158302011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bruno AC, Pavan TZ, Baffa O, Carneiro AAO. A hybrid transducer to magnetically and ultrasonically evaluate magnetic fluids. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:2004-2012. [PMID: 24658731 DOI: 10.1109/tuffc.2013.2785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ultrasound, magnetic fields, and optical techniques have been explored for clinical diagnosis and therapy. However, these techniques have limitations. In this study, we constructed and characterized a transducer to magnetically and ultrasonically investigate samples labeled with magnetic particles. The transducer is a hybrid system consisting of an ac biosusceptometer (ACB) and an ultrasonic transducer. The basic operation principle consisted of measuring the magnetization and microvibrations of ferromagnetic particles (37 and 70 μm) mixed in yogurt and excited by an external alternating magnetic field generated by the ACB's excitation coils. The vibration of the ferromagnetic particles was measured in phantoms using a Doppler ultrasonic transducer; we verified the sensitivity to detecting the vibrations at low concentrations of ferromagnetic material (~1%). The responses of the susceptometer and Doppler ultrasound linearly depended on the voltage level applied to the magnetizing coils at low ferromagnetic particle concentrations (⩽ 5%). We also conducted a repeatability test on the prototype, which indicated a deviation of 0.94% and 0.25% in the Doppler and susceptometric measurements, respectively. We can conclude that the hybrid transducer technique has potential clinical applications.
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Ferrari PC, Grossklauss DBBDS, Alvarez M, Paixão FC, Andreis U, Crispim AG, Castro ADD, Evangelista RC, Miranda JRDA. A novel automated alternating current biosusceptometry method to characterization of controlled-release magnetic floating tablets of metronidazole. Drug Dev Ind Pharm 2013; 40:1123-31. [DOI: 10.3109/03639045.2013.809537] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Paixão FC, Corá LA, Américo MF, de Oliveira RB, Baffa O, Miranda JRA. Development of an AMR-ACB array for gastrointestinal motility studies. IEEE Trans Biomed Eng 2012; 59:2737-43. [PMID: 22996723 DOI: 10.1109/tbme.2012.2208748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The association between anisotropic magnetoresistive (AMR) sensor and AC biosusceptometry (ACB) to evaluate gastrointestinal motility is presented. The AMR-ACB system was successfully characterized in a bench-top study, and in vivo results were compared with those obtained by means of simultaneous manometry. Both AMR-ACB and manometry techniques presented high temporal cross correlation between the two periodicals signals . The contraction frequencies using AMR-ACB were 73.9 ± 7.6 mHz and using manometry were 73.8 ± 7.9 mHz during the baseline . The amplitude of contraction using AMR-ACB was 396 ± 108 μT·s and using manometry were 540 ± 198 mmHg·s during the baseline. The amplitudes of signals for AMR-ACB and manometric recordings were similarly increased to 86.4% and 89.3% by neostigmine, and also decreased to 27.2% and 21.4% by hyoscine butylbromide in all animals, respectively. The AMR-ACB array is nonexpensive, portable, and has high-spatiotemporal resolution to provide helpful information about gastrointestinal tract.
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Woo SHA, Mohy-Ud-Din Z, Cho JH. Telemetry capsule for measuring contractile motion in the small intestine. Biomed Microdevices 2012; 15:63-72. [DOI: 10.1007/s10544-012-9688-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Agostinho M, Américo MF, Marques RG, Zandoná EA, Stelzer M, Corá LA, Andreis U, Oliveira RB, Miranda JRA. AC Biosusceptometry as a method for measuring gastric contraction. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2011; 2010:5740-3. [PMID: 21097331 DOI: 10.1109/iembs.2010.5627855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The aim of this study was to validate the alternate current biosusceptometry (ACB) for monitoring gastric contractions in rats. In vitro data were obtained to establish the relationship between ACB and the strain-gauge (SG) signal amplitude. In vivo experiments were performed on rats with magnetic markers and SGs previously implanted under the gastric serosa. The effects of the prandial state in gastric motility profiles were obtained. The correlation between in vitro signal amplitudes was strong (R = 0.989). The temporal cross-correlation between the ACB and SG signal amplitude was higher in the postprandial than in the fasting state. Irregular signal profiles, low contraction amplitudes, and smaller signal-to-noise ratios explained the poor correlation for fasting-state recordings. The contraction frequencies using ACB were 0.068 ± 0.007 Hz (postprandial) and 0.058 ± 0.007 Hz (fasting) and those using SG were 0.066 ± 0.006 Hz (postprandial) and 0.059 ± 0.008 Hz (fasting) (P < 0.003). When a magnetic tracer was ingested, there was a strong correlation and a small phase-difference between techniques. We conclude that ACB provides an accurate and sensitive technique for studies of GI motility in the rat.
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Américo MF, Marques RG, Zandoná EA, Andreis U, Stelzer M, Corá LA, Oliveira RB, Miranda JRA. Validation of ACB in vitro and in vivo as a biomagnetic method for measuring stomach contraction. Neurogastroenterol Motil 2010; 22:1340-4, e374. [PMID: 20874731 DOI: 10.1111/j.1365-2982.2010.01582.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND The aim of this study was to validate a biomagnetic method (alternate current biosusceptometry, ACB) for monitoring gastric wall contractions in rats. METHODS In vitro data were obtained to establish the relationship between ACB and the strain-gauge (SG) signal amplitude. In vivo experiments were performed in pentobarbital-anesthetized rats with SG and magnetic markers previously implanted under the gastric serosa or after ingestion of magnetic material. Gastric motility was quantified from the tracing amplitudes and frequency profiles obtained by Fast Fourier Transform. KEY RESULTS The correlation between in vitro signal amplitudes was strong (R = 0.989). The temporal cross-correlation coefficient between the ACB and SG signal amplitude was higher (P < 0.0001) in the postprandial (88.3 ± 9.1 V) than in the fasting state (31.0 ± 16.9 V). Irregular signal profiles, low contraction amplitudes, and smaller signal-to-noise ratios explained the poor correlation between techniques for fasting-state recordings. When a magnetic material was ingested, there was also strong correlation in the frequency and signal amplitude and a small phase-difference between the techniques. The contraction frequencies using ACB were 0.068 ± 0.007 Hz (postprandial) and 0.058 ± 0.007 Hz (fasting) (P < 0.002) and those using SG were 0.066 ± 0.006 Hz (postprandial) and 0.059 ± 0.008 Hz (fasting) (P < 0.005). CONCLUSIONS & INFERENCES In summary, ACB is reliable for monitoring gastric wall contractions using both implanted and ingested magnetic materials, and may serve as an accurate and sensitive technique for gastrointestinal motility studies.
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Affiliation(s)
- M F Américo
- Departamento de Física e Biofísica, Instituto de Biociências, UNESP – Univ Estadual Paulista, Botucatu, São Paulo, Brazil.
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Paixao FC, Quini CC, Baffa O, Miranda JRDA. A novel device with 36 channels for imaging and signal acquisition of the gastrointestinal tract based on AC biosusceptometry. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2010:6457-60. [PMID: 21096717 DOI: 10.1109/iembs.2010.5627341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The alternate current biosusceptometry (ACB) is a biomagnetic technique used to study some physiological parameters associated with gastrointestinal (GI) tract. For this purpose it applies an AC magnetic field and measures the response originating from magnetic marks or tracers. This paper presents an equipment based on the ACB which uses anisotropic magnetoresistive (AMR) sensors and an inexpensive electronic support. The ACB-AMR developed consists of a square array of 6×6 sensors arranged in a first-order gradiometer configuration with one reference sensor. The equipment was applied to capture magnetic images of different phantoms and to acquire gastric contraction activity of healthy rats. The results show a reasonable sensitivity and spatial-temporal resolution, so that it may be applied for imaging of phantoms and signal acquisition of the GI tract of small animals.
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Affiliation(s)
- Fabiano C Paixao
- Faculdade de Física, Pontifical Catholic University of Rio Grande do Sul - PUCRS, Av. Ipiranga, 6681 - Partenon, 90619-900, Porto Alegre-RS, Brazil.
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Miranda JRA, Corá LA, Américo MF, Romeiro FG. AC biosusceptometry technique to evaluate the gastrointestinal transit of pellets under influence of prandial state. J Pharm Sci 2010; 99:317-24. [PMID: 19431208 DOI: 10.1002/jps.21794] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Multiparticulate dosage forms have been proposed when distal regions of gastrointestinal tract are desirable as target of drugs. It is known that physiological parameters might interfere with the processes related to the drug delivery and absorption and therefore, it is essential to evaluate the behavior of such delivery systems in vivo. The aim of this study was to propose the AC Biosusceptometry technique as a noninvasive and radiation free device to evaluate the gastrointestinal transit of a magnetic multiparticulate dosage form in healthy volunteers under fasting and fed conditions. Magnetic pellets were prepared by the powder layering method of ferrite on nonpareils sugar beads and coated by using Eudragit. Our data showed that the AC Biosusceptometry technique was able to monitoring the gastrointestinal transit of pellets presenting similar profiles as demonstrated by standard techniques. Food intake has markedly influenced the gastric emptying as well as the colon arrival and the small intestine transit of magnetic pellets.
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Affiliation(s)
- José Ricardo A Miranda
- Department of Physics and Biophysics, Biosciences Institute, IBB, Sao Paulo State University, UNESP, PO Box 510, 18618-000 Botucatu, Sao Paulo, Brazil
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Bruno AC, Baffa O, Carneiro AO. Hybrid system for magnetic and acoustic measurement. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2009:761-4. [PMID: 19964487 DOI: 10.1109/iembs.2009.5334067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In order to improve the spatial resolution of Biosusceptometry of Alternate Current (BAC), we are suggesting the coupling of a Doppler ultrasonic transducer with the BAC system. The Doppler transducer obtains information from the vibration of ferromagnetic particles immersed in a visco-elastic medium when it is excited by an alternating magnetic field. In this case, the same magnetic particles used as contrast for susceptometric measurement also will work as contrast for the Doppler measurement. In this work, we present the characterization of the hybrid system for susceptometric and acoustic measurements simultaneously. It was observed that the susceptometric and Doppler ultrasound signal have the same profile and maximum amplitude for frequency of magnetizing field about 200 Hz. When using ferrite particles as magnetic contrast mixed with yogurt as based material, the susceptometric and Doppler measurement have sensitivity for concentration of particles as low as 1%. The sensitivity of the Doppler is dependent of the gradient of magnetic field over the sample. In this work, the magnetic field 5 cm far from the face of the transducer was 70 microT/volts.
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Affiliation(s)
- A C Bruno
- Departamento de Física e Matemática, Universidade de São Paulo, Brazil.
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Américo MF, Oliveira RB, Corá LA, Marques RG, Romeiro FG, Andreis U, Miranda JRA. The ACB technique: a biomagentic tool for monitoring gastrointestinal contraction directly from smooth muscle in dogs. Physiol Meas 2009; 31:159-69. [DOI: 10.1088/0967-3334/31/2/003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Américo MF, Miranda JRA, Corá LA, Romeiro FG. Electrical and mechanical effects of hyoscine butylbromide on the human stomach: a non-invasive approach. Physiol Meas 2009; 30:363-70. [PMID: 19282558 DOI: 10.1088/0967-3334/30/4/002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Due to the importance of motility in a number of gastrointestinal disorders, efforts have been made to evaluate both gastric motility counterparts: electrical activity and mechanical activity. The present work aimed to propose a new approach, associating AC biosusceptometry (ACB) and electrogastrography (EGG), to noninvasively monitoring mechanical and electrical gastric activity, respectively. Fourteen volunteers ingested a test meal and their gastric activity was evaluated by EGG and ACB at a baseline and after 20 mg of i.v. hyoscine butylbromide. ACB and EGG showed a similar signal pattern and high temporal correlation. Hyoscine butylbromide decreased the mechanical motility index (MI) by 50.9%, while for electrical MI the reduction was 36.5%. Delayed times to onset (mean+/-SD: 50+/-15 versus 40+/-20 s; P<0.01) and the inhibitory effect (16+/-4 versus 14+/-5 min; P<0.01) were calculated for ACB and EGG, respectively. ACB and EGG emerged due to their interesting nature, noninvasiveness and low cost to evaluate gastric motility. Our approach associating ACB and EGG allowed monitoring and quantification of the effects of an anticholinergic drug in gastric electrical activity and contractile activity in humans.
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Affiliation(s)
- Madileine F Américo
- Departamento de Física e Biofísica, Instituto de Biociências, São Paulo State University-UNESP, Botucatu, São Paulo, Brazil
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Andreis U, Américo MF, Corá LA, Oliveira RB, Baffa O, Miranda JRA. Gastric motility evaluated by electrogastrography and alternating current biosusceptometry in dogs. Physiol Meas 2008; 29:1023-31. [PMID: 18698113 DOI: 10.1088/0967-3334/29/9/002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Association techniques could be the answer for evaluating electromechanical coupling and gastric emptying under basal conditions and after administration of drugs. Electrogastrography (EGG) and alternating current biosusceptometry (ACB) emerged due to their interesting nature, noninvasiveness and low cost. The aims were to examine in dogs the effect of erythromycin on gastric emptying by ACB and electrical and motor responses to erythromycin and propranolol by ACB and EGG respectively. Twelve beagle dogs ingested a solid test meal on separate days. Under anesthesia, gastric motility was evaluated by EGG and ACB after erythromycin and propranolol administration. Without anesthesia, gastric emptying was assessed under basal conditions and after erythromycin by ACB. ACB and EGG showed a strong temporal correlation. Erythromycin and propranolol presented the same profile with different power ratios; the amplitude increased whereas frequency decreased. Also, erythromycin administration hastened gastric emptying while reducing the orocaecal transit time. There is a demand for reliable, easy-to-perform and comfortable techniques to record gastric emptying and gastric activity in medicine and veterinary practice. In summary, the association of ACB with EGG accompanied by an appropriate animal model is promising for evaluating effects of drugs in gastric myoelectrical and contractile activity.
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Affiliation(s)
- Uilian Andreis
- Departamento de Física e Biofísica, IBB, São Paulo State University-UNESP, Botucatu, São Paulo, Brazil
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Paixão FC, de Moraes R, Stelzer M, Corá LA, Américo MF, Andreis U, Oliveira RB, Baffa O, de A Miranda JR. A novel biomagnetic instrumentation with four magnetoresistive sensors to evaluate gastric motility. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2008; 2007:2215-8. [PMID: 18002430 DOI: 10.1109/iembs.2007.4352764] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A novel instrumentation using anisotropic magnetoresistive (AMR) sensors associated with magnetic coils excitation was developed to evaluate gastrointestinal tract motility parameters. The susceptometer has four sensors that were used to measure the gastric activity contractions (GAC) in anaesthetized dogs, its performance was evaluated by manometry with good results.
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Affiliation(s)
- Fabiano C Paixão
- Departamento de Física e Biofísica, IBB - Universidade Estadual Paulista, Distrito de Rubião Júnior, S/N, 18.618-000, Botucatu-SP, Brazil
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Américo MF, Oliveira RB, Romeiro FG, Baffa O, Corá LA, Miranda JRA. Scintigraphic validation of AC Biosusceptometry to study the gastric motor activity and the intragastric distribution of food in humans. Neurogastroenterol Motil 2007; 19:804-11. [PMID: 17883432 DOI: 10.1111/j.1365-2982.2007.00960.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Abnormal intragastric distribution of food (IDF) and a phasic contractility in the proximal stomach have been related to dyspeptic symptoms. Thus, the behaviour of the stomach and the proximal region, in particular, continues to attract attention and demand for reliable and comfortable techniques. The aims of this study were to employ AC Biosusceptometry (ACB) and scintigraphy to evaluate IDF and gastric motor activity in humans. Fifteen healthy volunteers ingested 60 mL of yogurt containing 2 mCi of 99mTc and 4 g of ferrite. Each volunteer had gastric motility and IDF evaluated twice on separate days; on one occasion by ACB and another by scintigraphy. Digital signal processing was performed in MatLab (Mathworks Inc., Natick, MA, USA). Results were expressed as mean +/- SD. Similar results of distal accumulation time (P < 0.001) were obtained for scintigraphy (6.93 +/- 3.25 min) and for ACB (7.04 +/- 3.65 min). Fast Fourier Transform revealed two dominant frequencies (P > 0.9). Besides the well-know frequency of 3 cpm, our results showed identical frequencies in proximal stomach recordings (P < 0.001) for scintigraphic (1.01 +/- 0.01 cpm) and ACB (0.98 +/- 0.06 cpm). In summary, our data showed that scintigraphy and ACB are promising techniques to evaluate several aspects of gastric motility. Moreover, ACB is non-invasive, radiation-free and deserves the same importance as conventional methods for this kind of analysis.
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Affiliation(s)
- M F Américo
- Departamento de Fisiologia, FMRP, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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Baffa O, Cora L, Americo M, Fonseca P, Oliveira R, A Miranda J. Magnetic images of pharmaceutical dosage forms in the human gastrointestinal tract. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2005:7254-7. [PMID: 17281954 DOI: 10.1109/iembs.2005.1616185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Oral administration with solid dosage forms is a common route in the drug therapy widely used. The drug release by the disintegration process occurs in several gastrointestinal tract (GIT) regions. AC Biosusceptometry (ACB) was originally proposal to characterize the disintegration process of tablets in vitro and in the human stomach, through changes in magnetic signals. The aim of this work was to employ a multisensor ACB system to monitoring magnetic tablets and capsules in the human GIT and to obtain the magnetic images of the disintegration process. The ACB showed accuracy to quantify the gastric residence time, the intestinal transit time and the magnetic images allowed to visualize the disintegration of magnetic formulations in the GIT. The ACB is a non-invasive, radiation free technique, completely safe and harmless to the volunteers and had demonstrated potential to evaluate pharmaceutical dosage forms in the human gastrointestinal tract.
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Affiliation(s)
- O Baffa
- Department of Physics and Mathematics, FFCLRP, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
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Romeiro FG, Corá LA, de Andreis U, Américo MF, Oliveira RB, Baffa O, Miranda JRA. A novel biomagnetic approach to study caecocolonic motility in humans. Neurogastroenterol Motil 2006; 18:1078-83. [PMID: 17109691 DOI: 10.1111/j.1365-2982.2006.00838.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Motility patterns play a major role in human colonic functions; however, its physiological significance is poorly understood. Several studies have been introducing the Alternating Current Biosusceptometry (ACB) as a valuable tool in gastroenterology and pharmaceutical research. Using gold standard techniques, great effort has been made to validate ACB as a method for measuring gastrointestinal motility in humans and animals. The aim of this study was to evaluate caecocolonic motility and its response to a meal in healthy volunteers. The results showed a dominant frequency of 3.17 +/- 0.13 cycles per minute (mean +/- SD) that remained unchanged even after a standardized meal (P > 0.01). The colonic response to a meal was recorded as a considerable increase in amplitude, reflected by motility index (P < 0.01) and was observed for all the volunteers. The caecocolonic motility could be assessed by the ACB providing new insights into physiological patterns of motility. Moreover, the method is non-invasive, radiation-free, cost-effective and independent of bowel preparation.
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Affiliation(s)
- F G Romeiro
- Departamento de Clínica Médica, FMB, Universidade Estadual Paulista - UNESP, Botucatu, São Paulo, Brazil
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Corá LA, Romeiro FG, Paixão FC, Américo MF, Oliveira RB, Baffa O, Miranda JRA. Enteric Coated Magnetic HPMC Capsules Evaluated in Human Gastrointestinal Tract by AC Biosusceptometry. Pharm Res 2006; 23:1809-16. [PMID: 16858651 DOI: 10.1007/s11095-006-9035-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 04/11/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE To employ the AC Biosusceptometry (ACB) technique to evaluate in vitro and in vivo characteristics of enteric coated magnetic hydroxypropyl methylcellulose (HPMC) capsules and to image the disintegration process. MATERIALS AND METHODS HPMC capsules filled with ferrite (MnFe2O4) and coated with Eudragit were evaluated using USP XXII method and administered to fasted volunteers. Single and multisensor ACB systems were used to characterize the gastrointestinal (GI) motility and to determine gastric residence time (GRT), small intestinal transit time (SITT) and orocaecal transit time (OCTT). Mean disintegration time (t50) was quantified from 50% increase of pixels in the imaging area. RESULTS In vitro and in vivo performance of the magnetic HPMC capsules as well as the disintegration process were monitored using ACB systems. The mean disintegration time (t50) calculated for in vitro was 25+/-5 min and for in vivo was 13+/-5 min. In vivo also were determined mean values for GRT (55+/-19 min), SITT (185+/-82 min) and OCTT (240+/-88 min). CONCLUSIONS AC Biosusceptometry is a non-invasive technique originally proposed to monitoring pharmaceutical dosage forms orally administered and to image the disintegration process.
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Affiliation(s)
- Luciana A Corá
- Departamento de Física e Biofísica, IBB, Universidade Estadual Paulista-UNESP, Distrito Rubião Jr, s/n, CXP 510, CEP 18618-000, Botucatu, São Paulo, Brazil
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Corá LA, Romeiro FG, Américo MF, Oliveira RB, Baffa O, Stelzer M, Miranda JRDA. Gastrointestinal transit and disintegration of enteric coated magnetic tablets assessed by ac biosusceptometry. Eur J Pharm Sci 2006; 27:1-8. [PMID: 16188432 DOI: 10.1016/j.ejps.2005.08.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Revised: 01/11/2005] [Accepted: 08/04/2005] [Indexed: 11/20/2022]
Abstract
The oral administration is a common route in the drug therapy and the solid pharmaceutical forms are widely used. Although much about the performance of these formulations can be learned from in vitro studies using conventional methods, evaluation in vivo is essential in product development. The knowledge of the gastrointestinal transit and how the physiological variables can interfere with the disintegration and drug absorption is a prerequisite for development of dosage forms. The aim of this work was to employing the ac biosusceptometry (ACB) to monitoring magnetic tablets in the human gastrointestinal tract and to obtain the magnetic images of the disintegration process in the colonic region. The ac biosusceptometry showed accuracy in the quantification of the gastric residence time, the intestinal transit time and the disintegration time (DT) of the magnetic formulations in the human gastrointestinal tract. Moreover, ac biosusceptometry is a non-invasive technique, radiation-free and harmless to the volunteers, as well as an important research tool in the pharmaceutical, pharmacological and physiological investigations.
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Affiliation(s)
- Luciana A Corá
- Department of Physics and Biophysics, Biosciences Institute, IBB, Laboratório de Biomagnetismo, Universidade Estadual Paulista, CXP 510, Rua Botucatu, São Paulo CEP 18618-000, Brazil
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Corá LA, Andreis U, Romeiro FG, Américo MF, Oliveira RB, Baffa O, Miranda JRA. Magnetic images of the disintegration process of tablets in the human stomach by ac biosusceptometry. Phys Med Biol 2005; 50:5523-34. [PMID: 16306649 DOI: 10.1088/0031-9155/50/23/007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Oral administration of solid dosage forms is usually preferred in drug therapy. Conventional imaging methods are essential tools to investigate the in vivo performance of these formulations. The non-invasive technique of ac biosusceptometry has been introduced as an alternative in studies focusing on gastrointestinal motility and, more recently, to evaluate the behaviour of magnetic tablets in vivo. The aim of this work was to employ a multisensor ac biosusceptometer system to obtain magnetic images of disintegration of tablets in vitro and in the human stomach. The results showed that the transition between the magnetic marker and the magnetic tracer characterized the onset of disintegration (t(50)) and occurred in a short time interval (1.1 +/- 0.4 min). The multisensor ac biosusceptometer was reliable to monitor and analyse the in vivo performance of magnetic tablets showing accuracy to quantify disintegration through the magnetic images and to characterize the profile of this process.
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Affiliation(s)
- L A Corá
- Departamento de Física e Biofísica, IBB, UNESP, Botucatu, SP, Brazil
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